Shears.



l'. W. FRANK.

SHEARS.

APPLICATION FILED MAR. 20. |915.

Patented May 25, 1915.

2 SHEETS-SHEET 1.

I I }i II' l INVENTOR U.) QIDW& El @0h-Ummm, wmn Gl/IMAQLA Patented May 25, 1915.

2 SHEETS-SHEET 2.

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l. W. FRANK.

SHEARS.

AP'PLICATloN FILED MAR.20,1915.

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Isaac w. FRANK, or PITTSBURGH, PENNSYLVANIA, assIeNoE ro UNITED ENGINEER- NG' & FOUNDRY COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF rENNsvEvaNIa.

' ,l Specification of )Letters Patent.

SHEARS.

Patenten may es, Iers.

appneaeoa mea Ema 2o, i915. serial No. 15,750.

Tov all whom it may concern:

Be it known that l, llsAAc W. FRANK, a

-citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful improvement in `Shears, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification, in which- Figure l is a side elevation, partly broken away, of a shear embodying my invention. Figs. 2 and 3 are sectional detail views illustrating two different forms of my invention. Figa is a transverse section of the shear block shown in Fig. 2. Fig. 5 is a longitudinal section thereof. Fig.. 6 is a top plan view thereof, and Fig. 7 is a broken section showing the breaker block applied to the movable aw.

My invention relates to shears, and particularly shears of the lever or alligator jaw 7 type. ln shears of this type the lever jaw which carries the movable shear blade is frequently broken by reason of excessive strains, such as may be caused by the wedging between the blades of a piece being sheared. Illhis necessitates ex -ensive repairs.

The object of my invention isi to provide means of simple and e'ective character for preventing such breakage. l accomplish this object by providing a breaker block in one of the jaws, and preferably between the xed shear blade and the bed of the machine. lhis frangible block constitutes the weakest point in the structure when subjected to the wedging action previously described, so that in case of excessive wedging strains it gives way and relieves the strains on the other parts. Being of simple, inexpensive character, the block can be readily and cheaply replaced.

ln the accompanying drawing, referring to Figs. l to 6, inclusive, the numeral 2 designates the frame and bed of a lever shear, 3 the xed shear blade, and 4 the lever or jaw carrying the movable shear blade 5. 6 designates the driving motor, and 7 the actuating gearing. r)The shear may be in general of any well known construction and need not be described in detail. 8 is the breaker block which is seated between the fixed shear blade 3 and the abutment 9 on the bed 2, being secured by any suitable means, as by the bolts 10, which also hold the blade 3. rFhis block is shown as of general inverted U-shape in cross section, its depending legs being perforated for bolts l0. lit is preferably made of cast iron or other material which will break readily under excessive strains, such as would be caused by the wedging of a piece between the blades 3 and 5. ll designates a liner plate on which the blade 3 and breaker block 8 are seated. The nppery surface of the block 8 is preferably concaved, as indicated at 12, for the purpose of protecting it against undue downward pressure due to some projection, such as a projecting rivet head on the piece being sheared. The block may be reinforced by the internal webs 14. rllhese are shown as obliquely arranged (Fig. 6) to reduce their eective resistance to crushing strains.

lin Fig. 3 ll have shown a modified form of breaker block in which the legs 13 bear at their ends against the abutment 9a. That is to say, the block is placed with the legs extending horizontally instead of vertically.

lln Fig. 7 lt show another form of the invention in which, instead of applying the breaker block to the ixed jaw, l apply it to the movable jaw 4a. lln this form the construction is preferably generally the same as in the rst form, 8a being the U-shaped breaker block, l1a the liner plate, 5L the blade,.and 10a the bolts passing through the blade, the breaker block, and the movable jaw.

rllhe advantages of my invention will be readily apparent since it provides a simple and eective expedient' whereby breakage of the working parts of the shear is prevented. When the breaker block gives way it can be readily and quickly replaced at comparatively small expense.

l do not desirel to limit myself to the particular forms and arrangement of the breaker block as herein shown and described, as it is obvious that the form and arrangement may be changed in various ways without departing from the spirit and scope of my invention as defined in the appended claims.

l claim:

l. A shear having-one of its jaws provided with a frangible breaker block interposed between the blade and the rear part of the jaw, said block being adapted to give way under excessive pressure in a direction at substantially right angles to the plane of the shear blades; .substantially as described.

2. A shear having one of its jaws provided l.with a frangible breaker block interposed between the blade and the rear part of the jaw, said block being arranged to give way under excessive wedging action between .the blades; substantially as` described.

3. A shear of the lever or alligator type, having one of its jaws provided with a -frangible breaker block seated removably behind its blade, said block being arranged to give way under excessive wedging acti onr between the blades; substantially as described.

4.v A shear of the lever or alligator jaw one of its shear blades and the lateral abutment for said blade, said member being capable of breaking when subjected to an exf cessi've strain `due to a wedging action of said blade ;'substan tially as described.

5. A shear having a breaker block interposed laterally betweenits xed blade and an abutment on the shear bed, and a single securing means for .both the shear blade and the breaker block, substantially as `described. -f

6. A^ shear having one of its jaws provided with a rangible breaker block interposed laterally between the blade and the -rear part of the jaw, and a single securing means for lboth the blade and the breaker posed llaterally between the blade and the rear part of the jaw, saidmember being hollow with obliquely arranged internal webs; substantially as described.

9. A shear having a hollow breakable member interposed laterally between its fixed blade and the bed of the shear, said f member having a recessed upper surface, substantially as described.

l0. A shear having a hollow breakable member interposed laterally between its fixed blade and the bed of the shear, Said. i

member having a recessed upper surface and having obliquely arranged internal webs, substantially as described.

In testimony whereof, I have hereunto set my hand. l

ISAAC W. FRANK.

Witnesses: v

G. G. TRiLL, R. A. BALDERsoN. 

